The invention relates to a method and devices for monitoring the clamping pressure, which originates from an adjusting cylinder and with which the exchangeable electrode of an electric furnace is clamped at the free end of the electrode-supporting arm.
According to the state of the art, the electrode, exchangeably assigned to the electrode-carrying arm of electric furnaces, is clamped in the seat, provided for this purpose at the supporting arm with the help of a single stage cylinder, the piston rod of which, retracting or extending under the force of a spring, brings about the clamping of the electrode in the seat. Depending on the installed situation of the adjusting cylinder, the pressure springs are in the annular space or in the cylinder space at the bottom of the adjusting cylinder. The clamping is disengaged by supplying a pressure medium to the cylinder space at the bottom or to the annular space of the adjusting cylinder, under the action of which the extension and retraction of the piston rod against the force of the adjusting spring, which is located in the annular space 213 of the cylinder 21 and brings about the extension and retraction situation, takes place. In order to ensure that there is a sufficient clamping force for clamping the electrode while the operation is running, the clamping force must be checked at regular intervals in such a manner that, with the electrode removed from the electrode seat, a device, for measuring the clamping pressure and designed for the electrode and, with that, also for the seat, is transferred into the electrode seat and the cylinder or cylinders is/are adjusted. This type of monitoring is relatively time-consuming to the detriment of the running operation. It also does not exclude a release of the clamped electrode during the running operation in the case of a pressure drop, which was not detected initially, with corresponding consequences for the course of the operation.